There is a unique geological history behind the Lake Superior Agate that begins over a billion years ago. What we now know as North America was once a larger continent that we refer to as Laurentia. During the formation of Laurentia, tectonic plates moved greatly, the outcome of this movement resulted in Laurentia splitting apart. Lava erupted through the crust during the split and once it began to settle and cool, gas pocketed in cavities of porous rocks. Overtime, many elements along with water enriched in silica pervaded into these cavities as well. This is what the stripped bands of agates are derived from – layers of different minerals stacked upon each other.